10 people were injured as 2 train on Knott’s Berry Farm’s Pony Express(made by Zamperla rides,Italy) collided into each other on October 7, 2010. The collision was caused by one train not making it over the hill and rolling back in to the launch area( know as a roll back) however, instead of the ride stoping and launching again, it rolled back into the station, hiting the other train. The 10 people were rushed to the hospital to be checked on. The 10 injured said that they felted pain in there neck and/or back. Knott’s is not sure what cause the roll back. Here is a video link:
http://latimesblogs.latimes.com/lanow/2010/10/knotts-berry-farm-accident-occurs-after-roller-coster-car-fails-to-climb-tracks.html